Question

I m new to coding and i m trying to create a binary tree obtianed form the array. When i try to run it , i get a runtime error. Can someone explain what is wrong with this code.
tnode is the struct for storing the node and construct_tree is called to build the tree.

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>         
        struct tnode{
            int value;
            struct tnode *parent ;
            struct tnode *left;
            struct tnode *right;
        };

        typedef struct tnode node;


    node* construct_tree(int *a,int n){
        printf("where");        
        node *root, *temp, *traverse, *traverse_parent;
        root = (node*)malloc(sizeof(node));

        root->value = a[0];
        root->parent = NULL;
        root->left = NULL;    
        root->right = NULL;    
        traverse = root;
        printf("where1");    
        printf("\n%d",a[0]);
        int i=0;
        for(i=1;i<n;i++){
            temp = (node*)malloc(sizeof(node));
            temp->value = a[i];
            temp->left = NULL;
            temp->right = NULL;

            while(traverse == NULL){
                traverse_parent = traverse;
                if(traverse->value < a[i]) traverse = traverse->right;
                else traverse = traverse->left;            
            }
            temp ->parent = traverse_parent;        
            printf("\n a[i]: %d and parent : %d",a[i],traverse_parent->value);
        }
        return root;
    }


    int main(){
        int a[] = {5,3,7,6,11,1,4};
        node* root;
        printf("where2");        
        root = construct_tree(a,6);
        //tree_traversal(root);
    }

Answer 1

Your inner while is never executed since it’s initialized to root and never nullified. I suppose you would want to replace while(traverse == NULL) with while(traverse != NULL) and also reset the traverse back to root on each iteration of the for loop (after the while completion).